When long-term monitoring—from a few hours to multiple months—of human-generated signals (such as electrocardiogram (ECG), electroencephalogram (EEG) and electromyogram (EMG)) is required, currently available devices fall short of adequately meeting the requirements of both the clinician and patient. A medical patch is typically a thin, adhesive-coated flexible material applied to the skin, in this case, for medical monitoring or therapy (drug, electric stimulus, etc.) delivery. A patch may additionally be comprised of one part attached to the skin and a second part that includes electronics circuitry, a radio and a battery, which is in turn attached to the first (skin) part. For long-term monitoring applications, it may be important to leave the skin-contacting portion of the patch attached for the entire monitoring period. Not only will this yield the most consistent signals, but the patient's skin will experience less trauma resulting from the patch. Adhesives commonly used for attaching ambulatory electrodes or patches typically remove one or two layers of skin when they are pulled off, and repeated removals at the same body site can cause skin trauma and a painful rash. Reapplying a patch to a different site avoids the skin irritation, but is unlikely to produce identical signals in monitoring applications.
To accommodate leaving the electrodes in place for extended periods, a method for removing and replacing the electronics, radio and battery is needed. Replaceability of the electrodes/electronics is desirable for the following reasons including: replacing batteries, preventing damage to the electronics during swimming or bathing, replacing malfunctioning electronics, radios or battery, reducing discomfort during certain physical activities, eliminating interference while undergoing medical scanning procedures, and/or removing a battery or capacitor power supply for recharging.
It would be desirable to develop a wireless patch for long-term monitoring, including the ability to change out or swap the electronics circuitry, radio and battery, either as a single unit or in separate modules, without having to remove the electrodes contacting the patient's skin.